Re: spots and fish eyes

Fish eyes

Iv'e been wondering about fisheyes for years and just had a thought. What
made me wonder was why would a oily finger print made fisheyes not a
fingerprint shaped area of resitance to smooth washing of the water based
media. Why is the fisheye always perfactly round?

My current thought is that there is a threshhold that must be passed before
a spot on the paper can reject the water. So there is no half way rejection.
At some point the surface of the paper is too unwelcome for the water to
cover it, for the surface tension to be broken. But when the surface tension
is broken the surrounding water is formed into a circle around the resistant
spot by the surface tension. The fisheyes are probably all the same diameter
because there is a limit to the circular hole the sheet of water can hold
open without the surface tension jumping over the spot. So a larger area of
resistance to wetting will either show the same size fisheyes or none ( the
water will bridge the area). If the latter happens in gum coating the gum
will not be well adhered to the paper but you won't know it until the
emusion fall off as soon as it hits the water for developement. I would
guess that a thicker gum mix (more pigment or less water) could be brushed
over such spots without one being aware of them until developement. Another
reason to coat in thin layers.

The black spots you are reporting sound like gaps in the size. Perhaps there
is a production problem in their sizing consistancy. Perhaps bubbles in the
size if there is an external size they apply to this paper. Or Katherine's
idea of uneven wetness during shrinking. Bubbles at that stage. I've only
seen spots like this with really clumsy sizing (my application of size).

Jack

> From: "Christina Z. Anderson" <zphoto@montana.net>
> Reply-To: alt-photo-process-l@skyway.usask.ca
> Date: Mon, 08 Dec 2003 18:11:06 -0500
> To: alt-photo-process-l@skyway.usask.ca
> Subject: Re: spots and fish eyes
>
> PS, the dark spots happened immediately upon coating the print, not during
> development. You'll probably think I'm nuts for keeping on with the print,
> but I did do 3 coats, and all three did the same thing, so it wasn't the
> pigment choice, mixture, unevenness. I thought at first they'd disappear
> when I developed; they didn't, but then I found them quaint (we'll see if
> the faculty does) and kept doing more coats :)
> Chris
> ----- Original Message -----
> From: "Katharine Thayer" <kthayer@pacifier.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Monday, December 08, 2003 8:17 AM
> Subject: Re: spots and fish eyes
>
>
>> Chris,
>> If Ed's not available I'll be glad to throw this up on my website so
>> people can see what you're talking about, with these black spots. It
>> could be several things, but it depends what size the spots are, and
>> what they look like; it's difficult to diagnose without seeing them.
>>
>> If the fish eyes are what I'm picturing, where the emulsion opens up
>> holes as it's being brushed on, I'm totally with Jack on the cause: the
>> surface is not accepting the emulsion, and in my experience the most
>> likely cause for that is that the sizing is too thick or too slick. If
>> the sizing fills the tooth of the paper, then there's nothing for the
>> emulsion to hang onto. I like Jack's idea of Scotch-brite; I've used
>> sandpaper for the same purpose.
>> kt
>>
>> Dave S wrote:
>>>
>>> Christina,
>>>
>>> It is hard to visualize how the fish eyes look like. Could you describe
>>> more?
>>>
>>> Are you using acrylic sizing?
>>>
>>> Dave S
>>>
>>> ----- Original Message -----
>>> From: "Christina Z. Anderson" <zphoto@montana.net>
>>> To: "Alt List" <alt-photo-process-l@sask.usask.ca>
>>> Sent: Monday, December 08, 2003 7:53 AM
>>> Subject: spots and fish eyes
>>>
>>>> Good morning all!
>>>> I was wondering what the group consensus is on the cause of fish
> eyes
>>>> in gum printing? Is it because the gum/pigment mix is too "limpid"
> as
>>> one
>>>> old author said (too watery)? Or is there another cause? This same
>>> author
>>>> talked about gum, when being mixed with the dichromate, goes into
> little
>>>> microscopic globules that causes this. Or spotty sizing?
>>>> In the same vein, I have a most unusual print I did this week
> that I
>>>> would love Ed Buffaloe to show on his site (Ed?); it is really funny.
> It
>>>> fits with my project, which is using negs from my dad's collection
> from
>>> the
>>>> late 20's to the late 40's, digitizing the odd shaped negs, and
> printing
>>>> them out so they look like when people were trying to make black and
> white
>>>> color (can you tell I am not very eloquent this morning...) Anyway,
> there
>>>> are all these black spots all over one side, and a line down thru the
>>> middle
>>>> that looks like water damage. I am very sure it is uneven sizing of
> the
>>>> Fabriano paper--probably due to operator error in that with my
> shrinking
>>> of
>>>> the paper I put one too many pieces of paper in my bathtub and did not
>>>> agitate enough, or perhaps it could be manufacturer error. Anyone
> have a
>>>> similar problem?
>>>> Chris
>>>>
>>>>
>>>>
>>>>
>
Received on Mon Dec 8 22:01:15 2003